1. Field of the Invention
The present invention generally relates to the art of vehicle maintenance, and more specifically to an automated wireless preventive maintenance monitoring system for a vehicle such as a magnetic levitation train.
2. Description of the Related Art
Magnetic levitation (MAGLEV) trains are currently being developed and placed into service, and offer numerous advantages over conventional diesel and electric powered trains. Whereas the engine and cars of conventional trains roll on wheels which are guided by tracks, MAGLEV trains are levitated above guideways and propelled by magnetic fields.
An overview of a typical MAGLEV train system is presented in an article entitled "TRANSRAPID 06 II PERFORMANCE AND CHARACTERISTICS" by L Miller, International Conference on MAGLEV and Linear Drives, Las Vegas, May 1987, pp. 155-162.
Since the cars of MAGLEV trains do not make rolling contact with the guideways while traveling, frictional forces are minimal and operational speeds of up to 500 km/hr are attainable with low strain on the guideways. MAGLEV trains are extremely smooth and quiet in operation, and do not create environmental pollution. They are also are lighter in weight, more reliable, and easier to maintain than conventional trains.
MAGLEV trains, as well as virtually all other vehicles, must be properly maintained to ensure reliable operation. Well planned and careful maintenance is especially important in high speed vehicles such as trains which are used for public transportation, since a catastrophic failure can cause a tragic accident with enormous consequences.
Maintenance is conventionally performed by making periodic inspections to determine the operational condition of a vehicle, and repairing or replacing components which have malfunctioned or are excessively worn.
Preventive maintenance is also conventionally performed, which includes replacing components at intervals which are calculated as a percentage of their potential operating lifetime, or the number of operating hours after which the components can realistically be expected to malfunction or be worn beyond tolerance.
This percentage can be as low as 50% of the potential operating lifetime in the case of major components which are critical for the safe operation of a vehicle. These particular components also tend to be relatively expensive.
The effectiveness and efficiency of conventional vehicle maintenance are limited in several respects. Replacement of components at predetermined intervals is inefficient in that many of these components could have operated safely and reliably for a longer period of time. Premature replacement of components is also undesirable in terms of vehicle down time and maintenance cost.
Since maintenance inspections are performed periodically, a defective component can fail between scheduled inspections in a length of time which is significantly shorter than its replacement lifetime. This can cause a vehicle to break down catastrophically or at least require being taken out of service for repair.
Unscheduled maintenance is very expensive, since the vehicle must be repaired in the field or transported to a repair facility. In the case of a public transportation vehicle, a breakdown can cause a disruption in passenger service, causing inconvenience to the passengers and discouraging them from using public transportation. The danger of a tragic accident caused by an equipment malfunction cannot be overemphasized.